(1) Field of the Invention
The present invention relates to a system and method for communicating a vehicle with a calling party, e.g., a base station, particularily but not exclusively suitable for informing the base station of a location of the vehicle in which the system is mounted.
(2) Background of the Art
Recently, many automotive vehicles have adopted, so called, (hand-free) automotive telephones as vehicle communication systems.
Such kinds of vehicular communication systems are exemplified by Japanese Patent Application First (Nonexamined) Publications sho 50-75706 published on June 21, 1976, sho 58-161100 published on Sept. 24, 1983, and sho 60-100715 published on June 4, 1985.
Furthermore, a Japanese Utility Model Application No. sho 61-164614 filed on Oct. 27, 1986 exemplifies one of the other vehicular communication systems which informs the base station of the instantanous location of the vehicle in which the communication system is mounted.
In the above-identified Japanese Utility Model Application, when a corresponding switch installed on a transceiver is turned on, a positional information and identification number allocated to the vehicle are transmitted to the base station, the positional information being derived from means, installed on the vehicle, for detecting a position of the vehicle.
The vehicular communication system disclosed in the above-identified Japanese Utility Model Application has a feature capable of informing the position of the vehicle in which the system is mounted to the base station according to its necessity.
However, when in the automotive telephones, the communications are carried out during the movement of the vehicle on roads, a circuit interruption occurs when the vehicle passes through tunnels or underpasses or otherwise when a circuit condition is worse. In this case, a redialing becomes necessary.
In addition, in the previously proposed vehicular communication system, a communication circuit for the automotive vehicles is used to inform the vehicular position to the base station. Therefore, when the circuit interruption occurs, the operator (usually the vehicle driver) confirms the occurrence of the circuit interruption and a manual operation is needed to cause the system to be activated. This follows that a speedy activation cannot be carried out in case of emergency and, in worst cases, the vehicular position cannot be informed to the base station in the case when no reoperation is possible.